225 research outputs found
Observations of the unidentified gamma-ray source TeV J2032+4130 by VERITAS
TeV J2032+4130 was the first unidentified source discovered at very high
energies (VHE; E 100 GeV), with no obvious counterpart in any other
wavelength. It is also the first extended source to be observed in VHE gamma
rays. Following its discovery, intensive observational campaigns have been
carried out in all wavelengths in order to understand the nature of the object,
which have met with limited success. We report here on a deep observation of
TeV J2032+4130, based on 48.2 hours of data taken from 2009 to 2012 by the
VERITAS (Very Energetic Radiation Imaging Telescope Array System) experiment.
The source is detected at 8.7 standard deviations () and is found to be
extended and asymmetric with a width of 9.51.2 along
the major axis and 4.00.5 along the minor axis. The
spectrum is well described by a differential power law with an index of 2.10
0.14 0.21 and a normalization of (9.5
1.6 2.2) 10TeV cm
s at 1 TeV. We interpret these results in the context of multiwavelength
scenarios which particularly favor the pulsar wind nebula (PWN) interpretation
A theory-based intervention to promote medication adherence in patients with rheumatoid arthritis: a randomized controlled trial
Introduction/objectives: Adherence to prescribed medication regimens is fundamental to the improvement and maintenance of the health of patients with rheumatoid arthritis. It is therefore important that interventions are developed to address this important health behavior issue. The aim of the present study was to design and evaluate a theory-based intervention to improve the medication adherence (primary outcome) among rheumatoid arthritis patients.
Methods: The study adopted a pre-registered randomized controlled trial design. Rheumatoid arthritis patients were recruited from two University teaching hospitals in Qazvin, Iran from June 2018 to May 2019 and randomly assigned to either an intervention group (n = 100) or a treatment-as-usual group (n = 100). The intervention group received a theory-based intervention designed based on the theoretical underpinnings of the health action process approach (HAPA). More specifically, action planning (making detailed plans to follow medication regimen), coping planning (constructing plans to overcome potential obstacles that may arise in medication adherence), and self-monitoring (using a calendar to record medication adherence) of the HAPA has been used for the treatment. The treatment-as-usual group received standard care.
Results: Data analysis was conducted based on the principle of intention to treat. Using a linear mixed-effects model (adjusted for age, sex, medication prescribed, and body mass index), the results showed improved medication adherence scores in the intervention group (loss to follow-up = 16) compared to the treatment-as-usual group (loss to follow-up = 12) at the 3-month (coefficient = 3.9; SE = 0.8) and 6-month (coefficient = 4.5; SE = 0.8) follow-up. Intervention effects on medication adherence scores were found to be mediated by some of the theory-based HAPA variables that guided the study.
Conclusion: The results of the present study support the use of a theory-based intervention for improving medication adherence among rheumatoid arthritis patients, a group at-risk of not adhering to medication regimens
Investigating the TeV Morphology of MGRO J1908+06 with VERITAS
We report on deep observations of the extended TeV gamma-ray source MGRO
J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory.
Previously, the TeV emission has been attributed to the pulsar wind nebula
(PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a
significance level of 14 standard deviations (14 sigma) and measure a photon
index of 2.20 +/- 0.10_stat +/- 0.20_sys. The TeV emission is extended,
covering the region near PSR J1907+0602 and also extending towards SNR
G40.5--0.5. When fitted with a 2-dimensional Gaussian, the intrinsic extension
has a standard deviation of sigma_src = 0.44 +/- 0.02 degrees. In contrast to
other TeV PWNe of similar age in which the TeV spectrum softens with distance
from the pulsar, the TeV spectrum measured near the pulsar location is
consistent with that measured at a position near the rim of G40.5--0.5, 0.33
degrees away.Comment: To appear in ApJ, 8 page
Discovery of Very High Energy Gamma Rays from 1ES 1440+122
The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85
GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes.
The observations, taken between 2008 May and 2010 June and totalling 53 hours,
resulted in the discovery of -ray emission from the blazar, which has a
redshift =0.163. 1ES 1440+122 is detected at a statistical significance of
5.5 standard deviations above the background with an integral flux of
(2.8) 10
cm s (1.2\% of the Crab Nebula's flux) above 200 GeV. The
measured spectrum is described well by a power law from 0.2 TeV to 1.3 TeV with
a photon index of 3.1 0.4 0.2.
Quasi-simultaneous multi-wavelength data from the Fermi Large Area Telescope
(0.3--300 GeV) and the Swift X-ray Telescope (0.2--10 keV) are additionally
used to model the properties of the emission region. A synchrotron self-Compton
model produces a good representation of the multi-wavelength data. Adding an
external-Compton or a hadronic component also adequately describes the data.Comment: 8 pages, 4 figures. Accepted for publication in MNRA
Serum calcitonin negative Medullary thyroid carcinoma
BACKGROUND: Medullary thyroid carcinomas (MTC) constitute about 5 to 7 % of thyroid neoplasms. They originate from parafollicular C cells which produce Calcitonin, a hormone which has an impact on calcium metabolism and represents the biochemical activity of MTC. In rare cases pre-operative serum calcitonin can be negative. CASE PRESENTATION: We report on a 73-year-old female patient with a rare case of a serum calcitonin negative medullary thyroid carcinoma who suffered fulminant post-operative course and died of multiple metastasis. CONCLUSION: This case shows that in very rare cases MTCs do not secrete calcitonin making diagnosis and tumour follow-up difficult. To this date, only few reports describing this combination of circumstances were found in the English literature
Deep Broadband Observations of the Distant Gamma-ray Blazar PKS 1424+240
We present deep VERITAS observations of the blazar PKS 1424+240, along with
contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV
Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar
resides at a redshift of , displaying a significantly attenuated
gamma-ray flux above 100 GeV due to photon absorption via pair-production with
the extragalactic background light. We present more than 100 hours of VERITAS
observations from three years, a multiwavelength light curve and the
contemporaneous spectral energy distributions. The source shows a higher flux
of (2.1) ph ms above 120 GeV in 2009 and
2011 as compared to the flux measured in 2013, corresponding to
(1.02) ph ms above 120 GeV. The measured
differential very high energy (VHE; GeV) spectral indices are
3.80.3, 4.30.6 and 4.50.2 in 2009, 2011 and 2013,
respectively. No significant spectral change across the observation epochs is
detected. We find no evidence for variability at gamma-ray opacities of greater
than , where it is postulated that any variability would be small and
occur on longer than year timescales if hadronic cosmic-ray interactions with
extragalactic photon fields provide a secondary VHE photon flux. The data
cannot rule out such variability due to low statistics.Comment: ApJL accepted March 17, 201
The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies
We performed a 4.5-month multi-instrument campaign (from radio to VHE gamma
rays) on Mrk421 between January 2009 and June 2009, which included VLBA,
F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other
instruments and collaborations. Mrk421 was found in its typical (non-flaring)
activity state, with a VHE flux of about half that of the Crab Nebula, yet the
light curves show significant variability at all wavelengths, the highest
variability being in the X-rays. We determined the power spectral densities
(PSD) at most wavelengths and found that all PSDs can be described by
power-laws without a break, and with indices consistent with pink/red-noise
behavior. We observed a harder-when-brighter behavior in the X-ray spectra and
measured a positive correlation between VHE and X-ray fluxes with zero time
lag. Such characteristics have been reported many times during flaring
activity, but here they are reported for the first time in the non-flaring
state. We also observed an overall anti-correlation between optical/UV and
X-rays extending over the duration of the campaign.
The harder-when-brighter behavior in the X-ray spectra and the measured
positive X-ray/VHE correlation during the 2009 multi-wavelength campaign
suggests that the physical processes dominating the emission during non-flaring
states have similarities with those occurring during flaring activity. In
particular, this observation supports leptonic scenarios as being responsible
for the emission of Mrk421 during non-flaring activity. Such a temporally
extended X-ray/VHE correlation is not driven by any single flaring event, and
hence is difficult to explain within the standard hadronic scenarios. The
highest variability is observed in the X-ray band, which, within the one-zone
synchrotron self-Compton scenario, indicates that the electron energy
distribution is most variable at the highest energies.Comment: Accepted for publication in A&A, 18 pages, 14 figures (v2 has a small
modification in the acknowledgments, and also corrects a typo in the field
"author" in the metadata
Complex machine-learning algorithms and multivariable logistic regression on par in the prediction of insufficient clinical response to methotrexate in rheumatoid arthritis
The goals of this study were to examine whether machine-learning algorithms outper-form multivariable logistic regression in the prediction of insufficient response to methotrexate (MTX); secondly, to examine which features are essential for correct prediction; and finally, to in-vestigate whether the best performing model specifically identifies insufficient responders to MTX (combination) therapy. The prediction of insufficient response (3-month Disease Activity Score 28-Erythrocyte-sedimentation rate (DAS28-ESR) > 3.2) was assessed using logistic regression, least absolute shrinkage and selection operator (LASSO), random forest, and extreme gradient boosting (XGBoost). The baseline features of 355 rheumatoid arthritis (RA) patients from the “treatment in the Rotterdam Early Arthritis CoHort” (tREACH) and the U-Act-Early trial were combined for analyses. The model performances were compared using area under the curve (AUC) of receiver operating characteristic (ROC) curves, 95% confidence intervals (95% CI), and sensitivity and specificity. Fi-nally, the best performing model following feature selection was tested on 101 RA patients starting tocilizumab (TCZ)-monotherapy. Logistic regression (AUC = 0.77 95% CI: 0.68–0.86) performed as well as LASSO (AUC = 0.76, 95% CI: 0.67–0.85), random forest (AUC = 0.71, 95% CI: 0.61 = 0.81), and XGBoost (AUC = 0.70, 95% CI: 0.61–0.81), yet logistic regression reached the highest sensitivity (81%). The most important features were baseline DAS28 (components). For all algorithms, models with six features performed similarly to those with 16. When applied to the TCZ-monotherapy group, logistic regression’s sensitivity significantly dropped from 83% to 69% (p = 0.03). In the current dataset, logistic regression performed equally well compared to machine-learning algorithms in the prediction of insufficient response to MTX. Models could be reduced to six features, which are more conducive for clinical implementation. Interestingly, the prediction model was specific to MTX (combination) therapy response
Anti-infliximab antibodies are already detectable in most patients with rheumatoid arthritis halfway through an infusioncycle: an open-label pharmacokinetic cohort study
Contains fulltext :
97636.pdf (publisher's version ) (Open Access)BACKGROUND: This study in patients with rheumatoid arthritis (RA) treated with infliximab describes prospectively the course of (anti)infliximab levels within an infusioncycle to assess at what moment patients develop low/no infliximab trough levels and/or detectable anti-infliximab levels. METHODS: Infliximab treated RA patients were included in this descriptive open-label cohort study. During one infusioncycle (anti-)infliximab levels were assessed just before and one hour after infusion, and subsequently at 50%, 75% and at the end of the infusioncycle (pre-infusion). RESULTS: 27 patients were included. The median infliximab levels decreased from 77.0 mg/l (p25-p75: 65-89) one hour after the infusion to pre-infusion levels of 0.0 mg/l (p25-p75: 0.0-3.1). In 7 (26%) patients pre-infusion anti-infliximab antibodies were detected; these antibodies were already present halfway through the infusioncycle in 5 of the 7 individuals. Patients with detectable pre-infusion anti-infliximab antibodies have significantly more often low/no infliximab levels (< 1 mg/l) halfway trough the infusioncycle (in 5/7 patients) compared to patients without detectable pre-infusion anti-infliximab antibodies (0/20 patients, p < 0.001). CONCLUSIONS: Most anti-infliximab forming patients have detectable anti-infliximab antibodies halfway through an infusioncycle, which implies that these patients are exposed to nontherapeutical infliximab levels during more than halve of their infusion cycle. As none of the patients without anti-infliximab antibodies had no/low-infliximab levels halfway through the infusioncycle, the presence of pre-infusion anti-infliximab antibodies seems a sensitive and specific predictor for no/low infliximab-levels
Differences between serum polar lipid profiles of male and female rheumatoid arthritis patients in response to glucocorticoid treatment
Analytical BioScience
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